For the third part of this series, Patient Options breaks down the OIG report detailing the red flags the OIG used to detect fraud.. This article will list the areas of concern that they found tended to be fraudulent.


This study is national in scope and is based primarily on paid Medicare claims for chiropractic services provided in 2013. See Appendix A for a full discussion of our methodology.

Questionable Chiropractic Payments

We developed four measures to identify paid claims that were questionable. We based these measures on previous OIG reports and fraud investigations, interviews with experts in chiropractic practice and fraud detection, and our own analysis. These four measures are summarized below:

Treatment Suggestive of Maintenance Therapy. A high average number of claims per beneficiary per chiropractor suggests billing for services that were not active treatment. Previous OIG work has found that as more services are provided to a beneficiary, it becomes more likely that services are medically unnecessary or maintenance treatment.

Potentially Upcoded Claims. A high average “physician work relative value unit” for a chiropractor’s claims suggests billing for services at a higher level than warranted.19 Only about 10 percent of all paid chiropractic services are for the highest CPT code, 98942. Previous OIG work found that almost half of chiropractic services with CPT code 98942 were upcoded.20

Potential Sharing of Beneficiaries. A high average percentage of a chiropractor’s beneficiaries who received services from other chiropractors suggests the misuse of beneficiary identification numbers. OIG investigations and interviews with experts informed us that chiropractors with a high percentage of beneficiaries receiving treatments from other chiropractors may be involved with fraud schemes, such as medical identity theft or kickback arrangements.

Unlikely Number of Services per Day. A high number of hours of services provided by a chiropractor on 1 day suggests billing for services of diminished quality and/or for services that were not rendered. We calculated these measures for each chiropractor and analyzed the distribution of chiropractors for each measure. For the first three measures, we used a statistical technique called the Tukey method to identify chiropractors who were outliers compared to other chiropractors. For these three measures, we considered a chiropractor’s payments to be unusually high, or questionable, if they were greater than the 75th percentile plus 1.5 times the interquartile range.21 For the fourth measure, we established a threshold of 16 hours per day based on our knowledge, experience, and discussions with experts.

Inappropriate Chiropractic Payments

We developed three measures to identify paid claims that did not meet Medicare requirements for payment. These three measures are summarized below:

Claims Lacking a Covered Primary Diagnosis. These claims lacked a primary diagnosis code that was covered by Medicare based on CMS’s guidance and the local coverage determination where the chiropractic service was provided.

Claims for Duplicate Services. These claims were for services provided on the same day for the same beneficiary with the same diagnosis and procedure codes and the same chiropractor.

Claims Lacking the AT Modifier. These claims lacked the AT modifier, which indicates active treatment and is required for payment.

Chiropractors with High Questionable Payments

After calculating the total amount of questionable payments paid to each chiropractor, we identified chiropractors who received high amounts of questionable payments. For these chiropractors, we determined their locations, past questionable payments, and the extent to which their beneficiaries received physical and occupational therapy services on the same day. We identified their locations using the ZIP Codes on their claims. We identified past questionable payments by analyzing chiropractic claims data from 2009–2012 using our measures of questionable payment. Finally, we analyzed Part B claims data for physical and occupational therapy services to determine the extent to which the beneficiaries of chiropractors with high questionable payments received physical and occupational therapy services on the same day as chiropractic services.


We did not conduct a medical record review to determine whether chiropractic services were medically necessary or had been coded correctly. The measures included in our analysis are not intended to be a comprehensive set of characteristics for identifying chiropractors with questionable and inappropriate payments. Moreover, the four measures that identify questionable payments used in this study do not provide conclusive evidence of improper or fraudulent payments. Rather, the measures are intended to identify Medicare payments to chiropractors that exceed those of other chiropractors in ways that raise program integrity concerns. Further investigation would be required to determine whether these chiropractors were paid for improper or fraudulent Medicare claims for chiropractic services.


This study was conducted in accordance with the Quality Standards for Inspection and Evaluation issued by the Council of the Inspectors General on Integrity and Efficiency.


All information sourced from OIG report OEI-01-14-00200 September 2015